An electrically driven compressor is known in the prior art, which compresses refrigerant circulating in a refrigerating cycle for an automotive air conditioner.
The electrically driven compressor comprises a compressor device for compressing refrigerant and an electric motor for driving the compressor device, both of which are encapsulated in a hermetically sealed housing.
It is so arranged in many cases that the refrigerant flows into the hermetically sealed housing to cool down the electric motor, which is rotated for driving the compressor device.
The refrigerant flowing into the housing is gas-phase refrigerant from an evaporator located at an upstream side of the refrigerating cycle.
It may, however, happen that the gas-phase refrigerant in a refrigerating cycle, in particular in a hermetically sealed housing will be condensed and changed to the liquid-phase refrigerant, for example at a cold ambient temperature in winter.
The gas-phase refrigerant has generally a higher electric resistance and therefore a lower conductive property, whereas the liquid-phase refrigerant has a lower electric resistance and therefore a higher conductive property.
In many cases, the electrically driven compressor is mounted in an automotive engine room at such a place which is lower in a vertical direction than other components constituting the refrigerating cycle. The liquid-phase refrigerant condensed in the refrigerating cycle likely flows into the hermetically sealed housing for the compressor, and thereby the liquid level of the refrigerant in the compressor may be easily increased.
Accordingly, various countermeasures are taken to prevent electrically conductive parts in the hermetically sealed housing from being contacted with the liquid-phase refrigerant.
An encapsulated electrically driven compressor is known as one of those countermeasures, in which the electrically conductive parts are arranged at an upper portion of the hermetically sealed housing, because the liquid-phase refrigerant is stored by gravitation in a lower (bottom) portion of the housing.
As another countermeasure, an encapsulated electrically driven compressor is also known, in which water proofing property of the electrically conductive parts is enhanced by completely molding those parts.
It would become, however, more difficult to meet a recent requirement of a smaller size, in the case that the electrically conductive parts are arranged at upper portions of the hermetically sealed housing to prevent them from being contacted with the liquid-phase refrigerant stored in the bottom portion of the housing.
It is further disadvantageous in that the molding method for the electrically conductive parts by resin would require a longer working hour, because the molding should be done after the electrically conductive parts are assembled into the hermetically sealed housing.